Global Warming Science: The Basics

Listening to Republicans talk about global warming is like listening to middle-schoolers talk about sex.  Lots of ignorant bluster, and not much else.

Larry Kudlow, Trump's senior economic advisor spewed word salad when asked by George Stephanopoulos about the UN IPCC report, “I’m not denying any climate change issues, George, I’m just saying, ‘Do we know precisely ― and I mean worth modeling ― things like how much of it is man-made, how much of it is solar, how much of it is oceanic, how much of it is rainforest and other issues?" Gibberish, straight up.

Nearly all of the basic science about global warming was known before the end of the 19th -- yes, 19th, not 20th -- century. The remaining piece was completed by the early 1960's: global warming was real and caused by human activity. Understanding the basic science starts with common sense life experience. The sun warms the Earth. The sun's effect is obvious. Early mornings are the coolest times of the day. Temperatures rise with the sun and continue to increase throughout the day. We see the sun's light, feel its warmth on our skin, and know it is cooler in the shade than in direct sunlight.

Then, in late afternoon or early evening, as the sun starts to set, temperatures drop. Where does the day's heat go? That's a question few people ponder. Nighttime cooling just happens. When I ask non-scientists, most just shrug or say, "Up." That is a reasonable answer because we know that heat rises. But, rises to where? And how? If the adage of heat rising is truly correct, then why is it cooler in the mountains than at low elevations? Why is the temperature outside an airplane about 40 below? "Up" doesn't really answer the question.

The mechanism of daytime warming is obvious but the mechanism of nighttime cooling is not. Why the difference? The answer helps explain why it's so easy to hoodwink so many people about global warming. Our senses tell us about daytime heating. We see the sun and feel its warmth. But, our senses fail when it comes to nighttime cooling. Our eyes and skin don't provide any information. The situation would be different if we could see infrared light. We can't. Yet, if we could, we would know as instinctively as we know about the sun's warmth that everything around us glows with infrared light. Warm objects glow more brightly than cool ones. And, it would be easy to understand that warmth gets broadcast up into the night sky. Infrared light streaming up from Earth, through the atmosphere and in to outer space carries the day's heat away. Temperatures drop.

Infrared eyesight would also let us know that air is not transparent to infrared light the way it is transparent to visible light. Some infrared wavelengths zip through the air unimpeded. Other wavelengths get absorbed by gases in the air. Carbon dioxide is the most significant of those gases. The absorbed light never makes it to outer space. It heats the carbon dioxide that, in turn, warms the rest of the atmosphere. When more carbon dioxide is added from burning fossil fuels, more of the infrared light gets absorbed. Less escapes into outer space. Nighttime cooling becomes less efficient. The planet warms.